1. Field of the Invention
The present invention relates to a weather strip that is mounted on a flange around a circumferential part of an opening in a vehicle body of a motor vehicle.
2. Description of the Related Art
A motor vehicle has opening portions such as a door opening, a luggage compartment or trunk opening and the like, and weather strips are individually mounted on flanges around circumferential parts of the opening portions formed in a vehicle body of the motor vehicle so as to establish seals between the circumferential parts of the openings in the vehicle body and respective mating members such as a door and a trunk lid.
When these weather strips are mounted on the circumferential parts of the openings in the vehicle body, the flanges formed around the circumferential parts of the vehicle body openings are inserted into trim portions of the weather strips which each have a substantially U-shaped cross section.
For example, as shown in FIG. 6, an opening portion at a rear luggage compartment or trunk of a motor vehicle is sealed by mounting a weather strip 110 on a flange 7 provided around a circumferential part 6 of the opening portion in a vehicle body of the motor vehicle so as to confront the perimeter of a lid for the rear trunk.
Namely, the weather strip 110 has a trim portion 120 which is mounted on the flange 7 and a hollow seal portion 140 having a hollow space inside which is brought into contact with a back surface of the trunk lid 2 so as to seal a gap defined therebetween, whereby the opening portion is sealed by the hollow seal portion 140 being brought into contact with the back surface of the trunk lid 2.
The trim portion 120 includes a sidewall 121 facing a vehicle's outer side or an external side of the flange 7, a sidewall 122 facing a vehicle's inner side or an internal sidewall 122 and a bottom wall 123 to thereby be given a substantially U-shaped cross section. In order to increase the holding of the flange 7 by the trim portion 120, an insert 129 made of a metal plate is embedded in the trim portion 120.
In the interior, having a substantially U-shape in section, of the trim portion 120, external flange holding lips 124, 125 and internal flange holding lips 126, 127 are formed on the interior surfaces of the external sidewall 121 and the internal sidewall 122, respectively, so as to extend to form a substantially inverted V-like shape in section towards the bottom wall 123 side of the interior of the trim portion 120.
When mounting the weather strip 110 on the flange 7, the trim portion 120 is mounted on the flange 7 provided around the peripheral part of the opening of the rear trunk from thereabove so that the flange 7 is inserted into the interior having the substantially U-shape in section of the trim portion 120. The external flange holding lips 124, 125 and the internal flange holding lips 126, 127 are provided to extend from the interior surfaces of the trim portion 120, and the holding force by the trim portion 120 is increased by the insert 129. In this configuration, the flange 7 is held by the flange holding lips 124, 125, 126, 127 so as to be held therebetween, so that not only is the posture of the weather strip 110 maintained, but also the weather strip 110 is prevented from being dislocated from the flange 7. As this occurs, the hollow seal portion 140, which is provided integrally at an upper portion of the trim portion 120, is brought into contact with the back surface of the outer circumferential part of the trunk lid 2 so as to seal a gap defined between the circumferential part 6 of the opening in the vehicle body and the trunk lid 2.
However, in many cases, the insert 120 is formed of metal due to increase the holding force of the trim portion 120, and this eventually increases the overall weight of the weather strip 110, which has been found not preferable from the viewpoint of meeting the trend of reducing the weights of vehicles.
Because of this, as shown in FIG. 7, there exists a weather strip 210 having a hollow seal portion 240 in which instead of embedding metal inserts in a trim portion 220, an external sidewall 221, an internal sidewall 222 and a bottom wall 223 have a substantially constant thickness and are formed of a hard rubber material or a hard resin material (for example, refer to Patent Document 1 and Patent Document 2). Note that making the thicknesses of the external sidewall 221 and others is to improve the shape stability at the time of extrusion.
However, in this case, since no metal insert is embedded, although the object to reduce the weight of the weather strip 210 can be achieved, the force with which the trim portion 220 holds the flange 7 is reduced, and there has happened sometimes a case in which the trim portion 220 gets easy to be dislocated from the flange 7. When the weather strip 210 is mounted at a corner portion of the opening portion in the vehicle body, since the weather strip 210 is bent, there has happened sometimes a case in which the holding lip 226 or the like is deformed inwardly (towards the sidewall from which it or the like extends) so that the holding lip 226 or the like gets easy to be dislocated from the flange 7 or a case in which the weather strip 210 (the trim portion 220) leans depending on a balance failure between a body seal lip 228 and the internal holding lips 226, 227.
Then, as shown in FIG. 8, there exists a weather strip 310 having a hollow seal portion 340 and a trim portion 320 in which a sponge member 324 having a trapezoidal cross section is formed on an interior surface of an external sidewall 321 of the trim portion 320, while internal holding lips 326, 327 are formed on an interior surface of an internal sidewall 322 so that a flange 7 is held between the sponge member and the internal holding lips (for example, refer to Patent Document 3). In this case, however, when attempting to mold a trim portion 320 having a substantially U-shape cross section into a shape resulting when it is mounted on the flange 7, a space is required between the sponge member 324 and the internal holding lips 326, 327, whereby the holding force (inserting force, dislocating force) relative to the flange 7 is reduced, and the seal performance is also reduced.    Patent Document 1: Japanese Patent No. 3752627    Patent Document 2: JP-2008-230258    Patent Document 3: JP-2001-341588